Normal versus asthmatic bronchiole

During an asthma attack, smooth muscles located in the bronchioles of the lung contract, narrowing the airways and decreasing the flow of air. Inflammation and excess mucus secretion can further decrease the amount of air flow.

Review Date: 3/3/2019

Reviewed By: Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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